U.S. patent application number 16/752127 was filed with the patent office on 2020-05-21 for edge ring for a substrate processing chamber.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Kadthala Ramaya NARENDRNATH, Govinda RAJ, Bopanna Ichettira VASANTHA, Simon YAVELBERG.
Application Number | 20200161165 16/752127 |
Document ID | / |
Family ID | 56127307 |
Filed Date | 2020-05-21 |
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United States Patent
Application |
20200161165 |
Kind Code |
A1 |
RAJ; Govinda ; et
al. |
May 21, 2020 |
EDGE RING FOR A SUBSTRATE PROCESSING CHAMBER
Abstract
An edge ring and process for fabricating an edge ring are
disclosed herein. In one embodiment, an edge ring includes an
annular body and a plurality of thermal breaks disposed within the
annular body. The thermal breaks are disposed perpendicular to a
center line of the annular body of the edge ring.
Inventors: |
RAJ; Govinda; (Santa Clara,
CA) ; NARENDRNATH; Kadthala Ramaya; (San Jose,
CA) ; VASANTHA; Bopanna Ichettira; (Bangalore,
IN) ; YAVELBERG; Simon; (Cupertino, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
56127307 |
Appl. No.: |
16/752127 |
Filed: |
January 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14975119 |
Dec 18, 2015 |
10553473 |
|
|
16752127 |
|
|
|
|
62094490 |
Dec 19, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/67017 20130101;
H01L 21/68735 20130101; C23C 16/4585 20130101; H01L 21/67098
20130101; B33Y 80/00 20141201; B33Y 10/00 20141201 |
International
Class: |
H01L 21/687 20060101
H01L021/687; C23C 16/458 20060101 C23C016/458; H01L 21/67 20060101
H01L021/67 |
Claims
1. A method for fabricating an edge ring embedded with a thermally
conductive material, the method comprising: forming an annular
body; and forming a plurality of thermal breaks within the annular
body, the plurality of thermal breaks having an orientation
perpendicular to a centerline of the annular body, each thermal
break interleaved within a material comprising the annular
body.
2. The method of claim 1, wherein forming the annular body of the
edge ring further comprises forming a gas distribution system
within the annular body.
3. The method of claim 1, further comprising: depositing a coating
on the annular body, the coating comprised of a material having a
lower coefficient of thermal conductivity relative to a material of
the annular body.
4. The method of claim 1, wherein forming a plurality of thermal
breaks within the annular body comprises: 3D printing the plurality
of thermal breaks within the annular body.
5. The method of claim 4, further comprising: hot isostatic
pressing the edge ring.
6. The method of claim 1, further comprising: installing a threaded
insert in the annular body.
7. The method of claim 1, further comprising: forming a plurality
of fins integral with a bottom surface of the annular body.
8. A method for fabricating an edge ring embedded with a thermally
conductive material, the method comprising: forming an annular body
comprising a first material; and forming a plurality of thermal
breaks comprising a second material having a higher coefficient of
thermal conductivity relative to the first material, wherein each
of the plurality of thermal breaks is encapsulated within the first
material of the annular body, the plurality of thermal breaks is
disposed perpendicular to a centerline of the annular body, and
configured to disperse heat laterally throughout the edge ring
while inhibiting axial heat transfer along the centerline.
9. The method of claim 8, wherein forming the annular body of the
edge ring further comprises forming a gas distribution system
within the annular body.
10. The method of claim 8 further comprising: depositing a coating
on the annular body, the coating comprising a third material having
a lower coefficient of thermal conductivity relative to the first
material.
11. The method of claim 10, wherein the third material of the
coating is a material selected from the group consisting of
zirconium oxide, carbon in diamond form, and quartz.
12. The method of claim 10, wherein the third material of the
coating comprises yttrium stabilized zirconium oxide.
13. The method of claim 10, wherein the coating has a thickness
between 100 to 200 microns.
14. The method of claim 8, wherein forming a plurality of thermal
breaks within the annular body comprises: 3D printing the plurality
of thermal breaks within the annular body.
15. The method of claim 14, further comprising: hot isostatic
pressing the edge ring.
16. The method of claim 8, further comprising: installing a
threaded insert in the annular body.
17. The method of claim 8, further comprising: forming a plurality
of fins integral with a bottom surface of the annular body.
18. A method of processing a substrate in a processing chamber,
comprising: placing a substrate on an edge ring supported by a
substrate support member within a processing chamber, the edge ring
comprising an annular body and a plurality of thermal breaks;
heating the substrate by a heater embedded in the substrate support
member; and dispersing heat laterally throughout the edge ring
while inhibiting axial heat transfer along a centerline of the
annular body, wherein the annular body comprises a first material,
the plurality of thermal breaks comprise a second material having a
higher coefficient of thermal conductivity relative to the first
material, and the plurality of thermal breaks are encapsulated
within the first material and disposed perpendicular to the
centerline of the annular body.
19. The method of claim 18, wherein the edge ring further comprises
a gas distribution system disposed within the annular body.
20. The method of claim 18, wherein the edge ring further
comprises: a coating comprising a third material having a lower
coefficient of thermal conductivity relative to the first material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 14/975,119 filed Dec. 18, 2015, which claims priority from U.S.
Provisional Application Ser. No. 62/094,490, filed Dec. 19, 2014,
each of which is hereby incorporated by reference in its
entirety.
BACKGROUND
Field
[0002] Embodiments described herein generally relate to an
apparatus for fabricating devices on a substrate. More
particularly, embodiments described herein provide an edge ring for
supporting a substrate in a processing chamber.
Description of the Related Art
[0003] In the processing of substrates, such as semiconductor
wafers and display panels, a substrate is placed on a support in a
processing chamber while suitable processing conditions are
maintained in the processing chamber. For example, a substrate can
be heated for either a deposition, etch or other semiconductor
fabrication process. During a semiconductor fabrication process, a
substrate may be supported by a supporting structure while energy
from above or below the substrate is utilized to heat the
substrate. In many processing chambers, an edge ring is utilized to
protect the substrate supporting structure while processing the
substrate.
[0004] FIG. 1 schematically illustrates a sectional view of a
conventional edge ring 100 used in a semiconductor processing
chamber. The supporting structure that supports the substrate and
edge ring 100 is not shown. The edge ring 100 has an inner diameter
slightly smaller than an outer diameter of a substrate 102 being
processed. During processing, an outer edge region 106 of the
substrate 102 is disposed above a supporting surface 104 of the
edge ring 100 so that the edge ring 100 extends partially below the
substrate 102. Thermal energy 110 may be directed to a bottom
surface of the substrate 102 below the substrate 102 and the edge
ring 100 to heat the substrate 102, for example using heaters
embedded in the substrate supporting structure. Plasma 108 and/or a
second heat source may be directed to a top surface of the
substrate 102 from above the edge ring 100 to further heat the
substrate 102.
[0005] Conventional edge rings 100, as shown in FIG. 1, can
sometimes become too hot, result in warping of the edge ring 100.
Warping of the edge ring 100 results in a decrease in tool uptime
should the edge ring 100 require replacement, and an increase in
particle generation.
[0006] Thus, there is a need for an improved edge ring.
SUMMARY
[0007] Embodiments described herein generally relate to an edge
ring for use in a substrate processing chamber. The edge ring has
an annular body. Disposed within the annular body of the edge ring
is a plurality of thermal breaks. The plurality of thermal breaks
is disposed perpendicular to a center line of the annular body.
[0008] In another embodiment, a method for fabricating an edge ring
is described herein. The method includes forming an annular body
and forming a plurality of thermal breaks layers within the annular
body. The plurality of thermal breaks is perpendicular to a
centerline of the annular body. Each thermal break is interleaved
within material comprising an annular body of the edge ring.
[0009] In yet another embodiment, a processing chamber is disclosed
herein. The processing chamber includes a substrate support member
and an edge ring. The substrate support member is configured to
support a substrate. The edge ring is supported by the substrate
support member. The edge ring is configured to extend below the
substrate supported by the substrate support member. The edge ring
includes an annular body and a plurality of thermal breaks disposed
within the annular body. The thermal breaks are disposed
perpendicular to a center line of the annular body of the edge
ring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the above recited features of
the present disclosure can be understood in detail, a more
particular description of the disclosure, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this disclosure and are therefore not to be considered limiting of
its scope, for the disclosure may admit to other equally effective
embodiments.
[0011] FIG. 1 schematically illustrates a sectional view of a
conventional edge ring used in a thermal processing chamber.
[0012] FIG. 2 schematically illustrates a partial sectional view of
a thermal processing chamber with an improved edge ring, according
to one embodiment.
[0013] FIG. 3 is an enlarged cross-sectional view of the improved
edge ring of FIG. 2, according to one embodiment.
[0014] FIG. 4 is a partial cross-sectional view of another
embodiment of an edge ring, according to one embodiment.
[0015] For clarity, identical reference numerals have been used,
where applicable, to designate identical elements that are common
between figures. Additionally, elements of one embodiment may be
advantageously adapted for utilization in other embodiments
described herein.
DETAILED DESCRIPTION
[0016] FIG. 2 illustrates a side view of a processing chamber 200
having an edge ring 202. The processing chamber 200 includes a
substrate support member 208 and a base 242. The substrate support
member 208 is coupled to the base 242. The substrate support member
208 includes a support assembly 204. The support assembly 204 may
be an electrostatic chuck assembly, a heater, a vacuum chuck
assembly, or other substrate support platform.
[0017] A purge ring 206 and the edge ring 202 are supported on the
substrate support member 208. The edge ring 202 is configured to
extend below a substrate 203 disposed on the support assembly 204
during processing. The edge ring 202 may further include a
plurality of thermal breaks 218, and may also include one or more
of a threaded insert 220, and a gas distribution system 210.
[0018] The gas distribution system 210 includes a gas passageway
214, a gas inlet 212, and a gas outlet 216. The threaded insert 220
is located on a bottom surface 222 of the edge ring 202 that faces
the purge ring 206. The threaded insert 220 is configured to
receive a fastener 226, such that the fastener 226 couples the
purge ring 206 to the edge ring 202. The threaded insert 220 is
made of a material such that the threaded insert 220 can withstand
the high internal crushing and shear stress generated during the
heating process without becoming inseparable from the fastener 226.
The edge ring 202 with threaded insert 220 and fastener 226 may
also be an integral part of the edge ring 202, which may be
machined out or 3D printed. The integral threaded insert 220 and
fastener 226 may act as a centering feature for the substrate.
[0019] The gas inlet 212, the gas outlet 216, and the gas
passageway 214 are disposed within the edge ring 202. The gas
passageway 214 is in fluid communication with both the gas inlet
212 and the gas outlet 216. The edge ring 202 is described with
more detail in FIG. 3.
[0020] The purge ring 206 is substantially annular in shape, which
together with the support assembly 204, bounds an inner cavity 228.
The inner cavity 228 is connected to a gas supply 230, for example,
by conduits (not shown) routed through the support assembly 204.
During processing, a purge gas is flowed into the inner cavity 228.
The purge gas in the inner cavity 228 flows through gas outlets 232
disposed near the inside perimeter of the purge ring 206. The gas
outlets 232 exist on a top surface of the purge ring 206 that faces
the edge ring 202. The gas outlets 232 are in fluid communication
with the gas inlet 212 of the edge ring 202. Thus, the purge gas
exiting the gas outlet 232 is supplied into the gas passageway 214
of the edge ring 202 via the gas inlet 212. The purge ring 206
further includes an exhaust conduit 234. The exhaust conduit 234 of
the purge ring 206 is in fluid communication with the gas outlet
216 of the edge ring 202, such that gas exiting the gas passageway
214 of the edge ring 202 through the gas outlet 216 can flow
through the exhaust conduit 234 of the purge ring 206 and be routed
out of the processing chamber 200.
[0021] The support assembly 204 supports the substrate 203 during
processing. The support assembly 204 is coupled with the base 242.
The support assembly 204 further includes an electrostatic chuck
236 and a cooling plate 238. The cooling plate 238 is disposed on
the base 242. The cooling plate 238 may include a plurality of
cooling channels (not shown) for circulating coolant therethrough.
The cooling plate 238 may be engaged to the electrostatic chuck 236
by an adhesive or any suitable engagement mechanism. The bottom of
the cooling plate 238 may be coated with a thermal barrier coating
to reduce thermal cross talk between the cooling plate 238 and the
electrostatic chuck 236.
[0022] The electrostatic chuck 236 may further include one or more
heaters (not shown). The one or more heaters may be coupled to one
or more heating power supplies 240. The one or more heaters may be
independently controllable. The one or more heaters enable the
electrostatic chuck 236 to heat the substrate 203 from the bottom
surface of the substrate 203 to a desired temperature, for example,
a temperature of about 300 degrees Celsius. To prevent excessive
heating of the edge ring 202 by the high temperature of the
electrostatic chuck 236, the edge ring 202 may include one or more
heat control mechanisms, such as thermal breaks 218, a thermal
barrier coating, and gas distribution system 210.
[0023] FIG. 3 illustrates a partial enlarged view of the edge ring
202 illustrating the one or more heat control mechanisms. The edge
ring 202 has an annular body 300. The annular body 300 may include
an outer band 302 and an inner band 304. The inner band 304 is
configured to extend partially below an edge of the substrate (not
shown) disposed on the substrate support member (as shown in FIG.
2) during processing. The outer band 302 includes an inner wall 306
that at least partially surrounds a periphery of the substrate. The
outer band 302 and inner band 304 are concentric about the
centerline of the annular body 300. The inner wall 306 of the outer
band 302 is connected to a ledge 314 of the inner band 304. The
ledge 314 of the inner band 304 extends inward from the inner wall
306 of the outer band 302 and terminates at a first annular
sidewall 308. The annular body 300 of the edge ring 202 may further
comprise a second annular wall 310 that extends downwards to form
an outer wall 312. In one example, the outer wall 312 may extend
down the length of the purge ring 206 of FIG. 2.
[0024] The inner band 304 of the edge ring 202 extends radially
inwards towards the central axis of the annular body 300 from the
inner wall 306 of the outer band 302 to form the ledge 314 which
extends below the substrate. The ledge 314 is below and parallel to
a top surface 316 of the outer band 302. The ledge 314 of the inner
band 304 is sized according to the size of the substrate and allows
for thermal expansion of the substrate. The ledge 314 of the inner
band 304 is sized to extend below a periphery of the substrate. The
inner band 304 can extend a sufficient distance beneath the
substrate, such as from about 0.1 cm to about 0.5 cm to protect the
support assembly 204.
[0025] FIG. 4 illustrates one embodiment of the edge ring 202. The
annular body 300 of the edge ring 202 may include a plurality of
fins 402. The fins 402 are configured to increase the surface area
of the structure by increasing the exposed surface of the edge ring
202. By increasing the exposed surface of the edge ring 202, the
thermal conductivity is increased, thus reducing the temperature
gradient and ultimately reducing deformation of the edge ring 202.
Additionally, the fins 402 may be configured such that a purge gas
can flow in the area between the edge ring 202 and the
electrostatic chuck 236 in addition to, or in lieu of, the purge
gas flowing through the gas passageway 214.
[0026] In one example, the fin 402 is a continuous circular wall
concentric with the outer band 302 and the inner band 304. The fin
402 may be positioned between the outer band 302 and the inner band
304. The fin 402 has a radius from the central axis. The radius of
the fin 402 may be designed to achieve the radial temperature
gradient or temperature profile of the edge ring 202 and thus,
reduce deformation of the edge ring 202 during heating. In another
example (as shown), the annular body 300 includes a plurality of
fins 402 forming a non-continuous circular wall concentric with the
outer band 302 and the inner band 304.
[0027] Referring back to FIG. 3, the annular body 300 further
includes the thermal breaks 218. The thermal breaks 218 are
disposed within the annular body 300 of the edge ring 202,
perpendicular to a center line 350 of the annular body 300. The
thermal breaks 218 extend through the length of the annular body
300 beneath the top surface 316 of the outer band 302. The thermal
breaks 218 are composed of a material having a different
coefficient of thermal conductivity relative to the material
comprising the annular body 300. For example, the thermal breaks
218 may be comprised of a thermally conductive material, such as,
graphite. When the substrate is heated by the electrostatic chuck
236, the plasma source, or both, the edge ring 202 may rise in
temperature. The thermal breaks 218 are configured to disperse the
heat laterally (radially) throughout the edge ring 202 while
inhibiting axial heat transfer, which functions to substantially
prevent overheating and warpage of the edge ring 202. Because of
the reduced and more uniform heating of the edge ring 202, the edge
ring 202 is less susceptible to warpage and particle
generation.
[0028] In another example, the annular body 300 of the edge ring
202 may alternatively or additional include the gas distribution
system 210 as described above. The gas distribution system 210 may
work with the thermal breaks 218 to reduce the heating of the edge
ring 202. As described above, the gas distribution system 210
allows a purge gas to flow through edge ring 202, thereby
transferring heat from the edge ring 202. The purge gas may be an
inert gas, for example, nitrogen. As the purge gas flows through
the gas passageway 214, the purge gas may cool the annular body 300
of the edge ring 202 to compensate for heating of the edge ring 202
by the chamber processes. When used with the thermal breaks 218,
the gas passageway 214 of the gas distribution system 210 may be
disposed parallel with the thermal breaks 218 to enhance
temperature uniformity.
[0029] In another embodiment, the thermal breaks 218 and the gas
distribution system 210 may extend down the length of the outer
wall 312 of the edge ring 202. The thermal breaks 218 and the gas
distribution system 210 may help cool the outer wall 312 of the
edge ring 202, which protects the periphery of the purge ring 206
from being heated by the chamber environment.
[0030] In addition to, or alternative to, one or both of the
thermal breaks 218 and gas distribution system 210, a thermal
barrier coating 332 may be disposed on one or more surfaces 316,
222 of the edge ring 202. For example, the thermal barrier coating
332 may be disposed on a bottom surface 222 of the edge ring 202.
The thermal barrier coating 332 may also extend down the length of
the outer wall 312 of the edge ring 202. The thermal barrier
coating 332 provides additional protection for the edge ring 202
from thermal energy emitted from the electrostatic chuck 236. The
thermal barrier coating 332 thus enhances temperature control
and/or uniformity across the substrate and the edge ring 202. The
thermal barrier coating 332 is made from a material having a lower
coefficient of thermal conductivity relative to the material of the
annular body 300, such as, for example, zirconium oxide, diamond
like carbon (DLC), quartz, or yttrium stabilized zirconium oxide. A
bonding layer (not shown) may be placed in-between the thermal
barrier coating 332 and the bottom surface 222 of the edge ring
202. In one example, the bonding layers may be 0.5 to 20 microns
thick. In another example, the thermal barrier coating 332 may be
100 to 200 microns thick.
[0031] The top surface 316 of the edge ring 202 may optionally be
bead blasted. The top surface 316 of the edge ring 202 is bead
blasted to increase the roughness of the surface. The roughened
surface of the edge ring 202 reduces arcing within the processing
chamber 200 and contributes to uniform deposition on the
substrate.
[0032] The edge ring 202 may be formed from a suitable material
according to the material of the substrate being processed. In one
example, the edge ring 202 may be formed from a material having a
similar thermal capacity as the material of the substrate. In
another example, the edge ring 202 may be formed from a silicon
carbide material for processing a silicon substrate.
[0033] In one embodiment, edge ring 202 may be manufactured using a
3D printing process. In the 3D printing process, thin layers are
progressively deposited and fused until the edge ring 202 is
complete. Each layer is applied by a nozzle of a 3D printer in a
pattern stored by a 3D drawing computer program that runs on a
computer (not shown). The thermal breaks 218 in the edge ring 202
may be formed using the 3D printing process. For example, a layer
comprising the annular body 300 of the edge ring 202 and a layer
comprising the thermal break 218 could be fabricated in an
uninterrupted operation by the 3D printer. The 3D printing approach
reduces expense and time required for conventional edge ring
manufacturing. The 3D printing approach also eliminates several
conventional edge ring manufacturing steps, such as molding,
casting, and machinating. Additionally, tight tolerances can be
achieved due to layer-by-layer printing approach. One printing
system can be used to manufacture a variety of different edge
rings, with or without the thermal breaks 218, simply by changing
the pattern stored in the 3D drawing computer program. The 3D
printed parts may be subjected to post processing processes, such
as hot isostatic pressing to minimize surface defects and
porosity.
[0034] The edge ring 202 may alternatively be manufactured through
a casting process or other forming process. During the casting
process, the annular body 300 of the edge ring 202 is embedded with
a thermally conductive material, i.e., the thermal breaks 218.
[0035] While the foregoing is directed to embodiments of the
present disclosure, other and further embodiments of the disclosure
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *